a compact and sharp-rejection ultra-wideband (uwb) microstrip band-pass filter (bpf) is developed using of left handed metamaterials realized by complementary split ring resonator (csrr). moreover, proposed structure consists of two doublets parallel coupling gaps at each side of a microstrip ring. in comparison with some other filters, this structure shows a significantly wider passband due to...

We introduce a fiber ring optical resonator based on adiabatic fused-fiber grating couplers. The coupling of a through fiber to the resonator is controlled by the strength of the fiber Bragg gratings. By using two of these couplers and incorporating erbium-doped (ED) fiber in the ring, we control the internal loss of the ring by pumping the ED fiber. The transmission spectra of the through port...

Here, we propose an add-drop and a channel drop filter based on two-dimensional photonic crystal all circular ring resonators. These structures are made of a square lattice of silicon rods with the refractive index n1=3.464 surrounded by air (with refractive index n2=1). The broadest photonic band gap occurs at the filling ratio of r/a = 0.17. Two linear defect W1 waveguides couple to the ring....

Ring resonator optical switches using electro-optic materials have been proposed. The propagation loss of the waveguides and the resonance characteristics of ring resonators with different refractive indices are simulated. The operation voltage is estimated based on the results of the simulations and is found to be 0.70V in the case of the ring resonator switch with a K(Ta, Nb)O3 core and KH2PO...

The frequency resolution of an active waveguide ring resonator spectrometer is fundamentally limited by spontaneous emission noise produced by the gain medium. A closed-form expression for this resolution is derived, and the result is used to determine the minimum, rms, angular rotation rate, random walk error achievable by an active ring resonator gyroscope. An active waveguide ring resonator ...

In the present paper, photoconductive and dielectric dependence oscillation characteristics of a single photorefractive ring resonator have been studied for the case of non-degenerate two-wave mixing in photorefractive materials by employing the plane-wave approximation method. The influence of photoconductivity and dielectric constant of photorefractive materials on frequency of oscillation an...

This is a continuation of our previous work [Opt. Express 16, 9155 (2008)]. In this paper we investigate the effect of nonuniform pumping on the modal properties of surface-emitting chirped circular grating lasers. By numerically solving the coupled-mode equations and matching the boundaries we compare and discuss the threshold pump levels and frequency detuning factors for three pumping profil...

In parallel to a stand-alone microsphere resonator and a planar ring resonator on a wafer, the liquid core optical ring resonator (LCORR) is regarded as the third type of ring resonator that integrates microfluidics with state-of-the-art photonics. The LCORR employs a micro-sized glass capillary with a wall thickness of a few microns. The circular cross section of the capillary forms a ring res...